One Santos player and eight employees have tested positive for COVID-19, the Brazilian Serie A club said on Monday.
In a statement, Santos said all of those infected were asymptomatic but had been isolated as a precaution, and their names were not disclosed for privacy reasons.
Santos added that antibody tests showed three other players had previously been in contact with the virus without knowing.
The results came after 24 players and 45 staff members were tested at Santos's training complex on Friday.